class TextFile: (source)
Provides a file-like object that takes care of all the things you commonly want to do when processing a text file that has some line-by-line syntax: strip comments (as long as "#" is your comment character), skip blank lines, join adjacent lines by escaping the newline (ie. backslash at end of line), strip leading and/or trailing whitespace. All of these are optional and independently controllable. Provides a 'warn()' method so you can generate warning messages that report physical line number, even if the logical line in question spans multiple physical lines. Also provides 'unreadline()' for implementing line-at-a-time lookahead. Constructor is called as: TextFile (filename=None, file=None, **options) It bombs (RuntimeError) if both 'filename' and 'file' are None; 'filename' should be a string, and 'file' a file object (or something that provides 'readline()' and 'close()' methods). It is recommended that you supply at least 'filename', so that TextFile can include it in warning messages. If 'file' is not supplied, TextFile creates its own using 'io.open()'. The options are all boolean, and affect the value returned by 'readline()': strip_comments [default: true] strip from "#" to end-of-line, as well as any whitespace leading up to the "#" -- unless it is escaped by a backslash lstrip_ws [default: false] strip leading whitespace from each line before returning it rstrip_ws [default: true] strip trailing whitespace (including line terminator!) from each line before returning it skip_blanks [default: true} skip lines that are empty *after* stripping comments and whitespace. (If both lstrip_ws and rstrip_ws are false, then some lines may consist of solely whitespace: these will *not* be skipped, even if 'skip_blanks' is true.) join_lines [default: false] if a backslash is the last non-newline character on a line after stripping comments and whitespace, join the following line to it to form one "logical line"; if N consecutive lines end with a backslash, then N+1 physical lines will be joined to form one logical line. collapse_join [default: false] strip leading whitespace from lines that are joined to their predecessor; only matters if (join_lines and not lstrip_ws) errors [default: 'strict'] error handler used to decode the file content Note that since 'rstrip_ws' can strip the trailing newline, the semantics of 'readline()' must differ from those of the builtin file object's 'readline()' method! In particular, 'readline()' returns None for end-of-file: an empty string might just be a blank line (or an all-whitespace line), if 'rstrip_ws' is true but 'skip_blanks' is not.
| Method | __init__ |
Construct a new TextFile object. At least one of 'filename' (a string) and 'file' (a file-like object) must be supplied. They keyword argument options are described above and affect the values returned by 'readline()'. |
| Method | close |
Close the current file and forget everything we know about it (filename, current line number). |
| Method | error |
Undocumented |
| Method | gen |
Undocumented |
| Method | open |
Open a new file named 'filename'. This overrides both the 'filename' and 'file' arguments to the constructor. |
| Method | readline |
Read and return a single logical line from the current file (or from an internal buffer if lines have previously been "unread" with 'unreadline()'). If the 'join_lines' option is true, this may involve reading multiple physical lines concatenated into a single string... |
| Method | readlines |
Read and return the list of all logical lines remaining in the current file. |
| Method | unreadline |
Push 'line' (a string) onto an internal buffer that will be checked by future 'readline()' calls. Handy for implementing a parser with line-at-a-time lookahead. |
| Method | warn |
Print (to stderr) a warning message tied to the current logical line in the current file. If the current logical line in the file spans multiple physical lines, the warning refers to the whole range, eg... |
| Class Variable | default |
Undocumented |
| Instance Variable | current |
Undocumented |
| Instance Variable | file |
Undocumented |
| Instance Variable | filename |
Undocumented |
| Instance Variable | linebuf |
Undocumented |
Construct a new TextFile object. At least one of 'filename' (a string) and 'file' (a file-like object) must be supplied. They keyword argument options are described above and affect the values returned by 'readline()'.
Open a new file named 'filename'. This overrides both the 'filename' and 'file' arguments to the constructor.
Read and return a single logical line from the current file (or from an internal buffer if lines have previously been "unread" with 'unreadline()'). If the 'join_lines' option is true, this may involve reading multiple physical lines concatenated into a single string. Updates the current line number, so calling 'warn()' after 'readline()' emits a warning about the physical line(s) just read. Returns None on end-of-file, since the empty string can occur if 'rstrip_ws' is true but 'strip_blanks' is not.
Push 'line' (a string) onto an internal buffer that will be checked by future 'readline()' calls. Handy for implementing a parser with line-at-a-time lookahead.
Print (to stderr) a warning message tied to the current logical line in the current file. If the current logical line in the file spans multiple physical lines, the warning refers to the whole range, eg. "lines 3-5". If 'line' supplied, it overrides the current line number; it may be a list or tuple to indicate a range of physical lines, or an integer for a single physical line.